1. Field of the Invention
The present invention relates to an imaging device, more specifically relates to an imaging device containing a flexible printed wiring board which is connected to an electronic component such as an image sensor provided as an element of a photographing optical system.
2. Description of the Related Art
In a retractable type of photographic lens using no mirrors or prisms as refractors for refracting an optical axis of a photographing optical system (photographing optical axis), it is generally impossible to make the length of the photographic lens, in a retracted state, shorter than the sum of the thickness of the optical elements of the photographing optical system in the optical axis direction. Nevertheless, there has been a demand for a further reduction in length of the retracted photographic lens to achieve an extra-short photographic lens. As a solution to this demand, the assignee of the prevent invention has proposed a zoom lens whose length, in a retracted state, is further reduced by radially retracting a part of the photographing optical system away from the photographing optical axis thereof. This zoom lens is disclosed in U.S. patent Publication No. US2003/0156832 A1.
Such an element retractable from the photographing optical axis can be not only a lens group but also an electronic component such as an image sensor (image pickup device) or a shutter device. A flexible printed wiring board (flexible PWB) is suitable for establishing electrical connections between this type of electronic component and an electronic circuit. Although various wiring structures of flexible printed wiring boards which are connected to an electronic component which moves along the photographing optical axis have been proposed, it is difficult to carry out wiring of a flexible printed wiring board connected to a type of electronic component which moves from an on-axis position, in which the electronic component is positioned on the photographing optical axis, to an off-axis position, in which the electronic component is positioned away from the photographing optical axis, because the motion of such an electronic component is different from those of conventional similar electronic components. For instance, in the case where an electronic element retractable from the photographing optical axis is moved in a direction different from the retracting direction of the electronic element from the photographing optical axis from when the electric element is positioned on the photographing optical axis, a physical load tends to be applied on the electronic element by the flexible printed wiring board, so that it is desirable that such physical loads be reduced as much as possible. It is also desirable for the flexible printed wiring board to be accommodated with high efficiency in a wiring space when the electronic component is retracted away from the photographing optical axis.